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path: root/fs/ext2/super.c
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Diffstat (limited to 'fs/ext2/super.c')
-rw-r--r--fs/ext2/super.c39
1 files changed, 25 insertions, 14 deletions
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 748d35afc902..860024392969 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -721,7 +721,8 @@ static loff_t ext2_max_size(int bits)
{
loff_t res = EXT2_NDIR_BLOCKS;
int meta_blocks;
- loff_t upper_limit;
+ unsigned int upper_limit;
+ unsigned int ppb = 1 << (bits-2);
/* This is calculated to be the largest file size for a
* dense, file such that the total number of
@@ -735,24 +736,34 @@ static loff_t ext2_max_size(int bits)
/* total blocks in file system block size */
upper_limit >>= (bits - 9);
+ /* Compute how many blocks we can address by block tree */
+ res += 1LL << (bits-2);
+ res += 1LL << (2*(bits-2));
+ res += 1LL << (3*(bits-2));
+ /* Does block tree limit file size? */
+ if (res < upper_limit)
+ goto check_lfs;
+ res = upper_limit;
+ /* How many metadata blocks are needed for addressing upper_limit? */
+ upper_limit -= EXT2_NDIR_BLOCKS;
/* indirect blocks */
meta_blocks = 1;
+ upper_limit -= ppb;
/* double indirect blocks */
- meta_blocks += 1 + (1LL << (bits-2));
- /* tripple indirect blocks */
- meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
-
- upper_limit -= meta_blocks;
- upper_limit <<= bits;
-
- res += 1LL << (bits-2);
- res += 1LL << (2*(bits-2));
- res += 1LL << (3*(bits-2));
+ if (upper_limit < ppb * ppb) {
+ meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb);
+ res -= meta_blocks;
+ goto check_lfs;
+ }
+ meta_blocks += 1 + ppb;
+ upper_limit -= ppb * ppb;
+ /* tripple indirect blocks for the rest */
+ meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) +
+ DIV_ROUND_UP(upper_limit, ppb*ppb);
+ res -= meta_blocks;
+check_lfs:
res <<= bits;
- if (res > upper_limit)
- res = upper_limit;
-
if (res > MAX_LFS_FILESIZE)
res = MAX_LFS_FILESIZE;